328 Chapter XI 



scorpion and demonstrated the absolute erroneousness of the story 

 of suicide which, had it been true, would have afforded a unique 

 example of voluntary death in animals. On carrying out the classic 

 experiment he observed that within this ring of fire the scorpion 

 is subjected to a very high temperature. When the temperature 

 reaches 40 C. the scorpion begins to grow weak and as the tempera- 

 ture approaches 50 C. it passes into a comatose condition. Moreover 

 Bourne showed that the scorpion's poison, which is fatal for large 

 spiders, insects, and vertebrates, was innocuous for individuals of the 

 species furnishing it. 



I can confirm all the statements of this English observer. 

 When I was studying the embryology of the scorpion I repeatedly 

 tried the experiment but the animal never committed suicide. 

 Further, I repeatedly assured myself of the innocuousness of the 

 scorpion's poison when injected into individuals of the same species, 

 and I was able to demonstrate most conclusively that the blood of the 

 scorpion is endowed with undoubted antitoxic power. The addition 

 of 0*1 c.c. of this blood to a dose of poison which kills mice in half- 

 an-hour is sufficient to enable a mouse injected with the mixture to 

 resist it completely. This antitoxic power is the same in the Scorpio 

 afer and in the Algerian Androctonus. An emulsion of the liver of 

 the scorpion, however, is absolutely incapable of preventing fatal 

 intoxication of mice. 



This case of antitoxic action is the only one I have been able to 

 demonstrate in an invertebrate. Must we regard it as a case of 

 natural innate antivenomous power or as something acquired during 

 the life of the animal? It is not easy to settle this question by 

 experiment We can certainly procure new-born scorpions and rear 

 them for some time, but the quantity of blood that can be got from 

 them is insufficient for injection for protective purposes. Scorpions 

 do not love one another and when kept together we often find them 

 engaged in fierce and mortal combat, the stronger killing the weaker 

 and sucking their blood. It is therefore possible that, in some stage 

 of their life, the scorpions find means of vaccinating themselves 

 against their own poison either through the intestine or as the result 

 [345] of punctures caused by the point of the tail. It would be very 

 interesting to study this question under favourable conditions, because 

 it is capable of throwing light on the problem of the origin of anti- 

 toxins, from a general point of view. Whichever view be taken, the 

 acquisition of any antitoxic property by the blood in the Invertebrata 



